1. Filed of the Invention
The present invention is related to a fluid jetting device for jetting/applying a fluid via a nozzle onto a subject, related to a fluid jetting head containing the fluid jetting device, and also, related to a fluid jetting apparatus containing the fluid jetting head, for jetting/applying a predetermined amount of fluids at a predetermined position.
2. Description of the Related Art
As techniques related to fluid jetting devices, fluid jetting heads, and fluid jetting apparatus, both ink jetting heads in which printing ink is used as fluids to be jetted/applied and printing apparatus containing such ink jetting heads have been known.
FIG. 19 indicates an ink jetting head disclosed in Japanese Laid-open Patent Application No. Hei-4-148936 as an example of the ink jetting head according to related art (fluid jetting device). The ink jetting head shown in this drawing, owns such a structure that a large number of nozzles 301 are arrayed in a column form, and also, chambers 302 having narrow plane shapes are arrayed in such a manner that these chambers 302 are alternately positioned opposite to each other on both sides with respect to the nozzle columns in order that one edges thereof are located at positions corresponding to the nozzles. Also, supply holes 303 are arranged at other edges of the chambers 302.
While an ink pool 304 which is commonly used for all of these chambers 302 is arranged at a layer which is different from the layer where the chambers 302 are arranged, this ink pool 304 is communicated with the respective chambers 302 via the supply holes 303. An actuator (not shown) is mounted on each of pressure applying plates which form one plane of each of the chambers 302. As to the actuator, a piezoelectric actuator constructed of a piezoelectric element will be explained.
In the ink jetting head shown in FIG. 19, since the above-described actuators are driven, the pressure applying plates are flexed in such a direction along which the volumes of the chambers 302 are reduced. As a result, ink stored in the chambers is compressed and then, ink droplets are jetted from the nozzles 301. Then, the ink jetting head is constructed as follows. After the ink droplets have been jetted, ink is refilled from ink pool sub-streams into the chambers via the supply holes 303 in accordance with such a condition that deformation of the pressure applying plates is recovered to the original shapes thereof so as to be prepared for next ink jetting operation.
Now, a more concrete structure of an ink jetting head will be conceived which may be analogized from the above-described structure shown as the prior art. FIG. 20 indicates one of such head structures which may be conceived from the above-described heads. This drawing is an overall structural diagram for schematically showing a fluid jetting device, and showing arrangements of nozzles 101, ink chambers 102, ink pool sub-streams 105, and an ink pool main stream 106.
In FIG. 20, while chambers 102 in which the nozzles 101 for jetting ink are provided are arranged adjacent to each other, these chambers 102 are connected to the common sub-stream 105. Since plural sets of sub-streams 105 to which the nozzles 101/ink chambers 120 are connected are provided, a matrix may be formed in a minimum unit. Also, the respective sub-streams 105 are connected to the main stream 106, and this main stream 106 is connected to an ink tank (not shown).
Normally, four colors including a black color and predetermined three primary colors are required in color printing operation. To realize color printing operation, as indicated in FIG. 21, four sets of unit devices 90, 91, 92, and 93 are preferably formed in such a manner that these four unit devices 90, 91, 92, 93 for the four colors are arrayed in order that dots having different dots may be easily formed at the substantially same positions. In this case, due to such a necessity that the dots having the plural colors are jet/applied to positions in the vicinity of the same dot position, a scanning direction of these devices is preferably selected to a lateral direction of this drawing within a printer apparatus.
In the structures shown in FIG. 20 and FIG. 21, since a plurality of sub-streams 105 are connected to a single set of a main stream 106, a width 106w of the main stream should be made wide so as to reduce a fluid resistance of the main stream 106. This is because if the fluid resistance is not lowered, then a sufficient amount of ink is not supplied to such sub-streams located far from the ink tank (namely, sub-streams located at upper positions in case of example shown in FIG. 20), and thus, a depletion of ink may occur.
However, if the main stream width 106w is made wide, then a lateral width 80 of the unit device 100 becomes wide, and therefore, the width of the head becomes wide. Then, when the head becomes large, the weight of this head is increased. Thus, there are such problems that the head can be hardly driven, a size of a printer apparatus which mounts thereon this head is increased, and also, manufacturing cost of this head is increased.
The present invention has been made to solve the above-described problems, and therefore, has an object to provide a fluid jetting device, a fluid jetting head, and a fluid jetting apparatus containing these fluid jetting devices/heads, capable of realizing a head designed for a more compact and lighter printer apparatus.
An other object of the present invention is to provide a fluid jetting devices, a fluid jetting head, and a fluid jetting apparatus containing these fluid jetting device/head, capable of reducing vibrations and noise, which are produced during operation thereof.
To achieve the above-described objects, according to a first aspect of the invention, there is provided a fluid jetting device for jetting fluid droplets onto a subject to be fluid-jetted, the fluid jetting device having a fluid pool, a plurality of chambers arranged in a matrix form and communicating to the fluid pool, the nozzle for jetting the fluid droplets onto the subject, a fluid supplying portion for supplying the fluid to the fluid pool. The fluid pool includes a first flow path elongating along a first direction and disposed in the vicinity of the fluid supplying portion and a plurality of second flow paths branching off from the first fluid path and elongating in a second direction perpendicular to the first fluid path. The first fluid path is connected to both end portions of each of second fluid paths. The second fluid paths are divided at a substantially center portion thereof.
According to a second aspect of the invention, there is provided a fluid jetting device for jetting fluid droplets onto a subject to be fluid-jetted, the fluid jetting device having a fluid pool, a plurality of chambers arranged in a matrix form and communicating to the fluid pool, the nozzle for jetting the fluid droplets onto the subject, a fluid supplying portion for supplying the fluid to the fluid pool. The fluid pool includes a first flow path elongating along a first direction and disposed in the vicinity of the fluid supplying portion and a plurality of second flow paths branching off from the first fluid path and elongating in a second direction perpendicular to the first fluid path. The first fluid path is connected to both end portions of each of second fluid paths.
According to a third aspect of the invention, there is provided a fluid jetting device for jetting fluid droplets onto a subject to be fluid-jetted, the fluid jetting device having a fluid pool, a plurality of chambers arranged in a matrix form and communicating to the fluid pool, a nozzle formed in each of the plurality of chambers, the nozzle for jetting the fluid droplets onto the subject, a fluid supplying portion for supplying the fluid to the fluid pool, and a plurality of fluid pressure applying portion for driving each of chambers. The fluid pool includes a first flow path elongating along a first direction and disposed in the vicinity of the fluid supplying portion and a plurality of second flow paths branching off from the first fluid path and elongating in a second direction perpendicular to the first fluid path. A ratio xe2x80x9cN2/N1xe2x80x9d of number xe2x80x9cN1xe2x80x9d of the chambers arrayed in the first direction to number xe2x80x9cN2xe2x80x9d of the chambers arrayed in the second direction is not smaller than 1.